Separation and identification of phenolic compounds in olive oil by coupling high-performance liquid chromatography with postcolumn solid-phase extraction to nuclear magnetic resonance spectroscopy (LC-SPE-NMR).

This study reports the first application of the hyphenated LC-SPE-NMR technique using postcolumn solid-phase extraction to the direct analysis of phenolic compounds in the polar part of olive oil. Apart from the identification and structure elucidation of simple phenols (hydroxytyrosol, tyrosol, vanillic acid, vanillin, p-coumaric acid, hydroxytyrosol, and tyrosol acetates), lignans (pinoresinol and 1-acetoxypinoresinol), flavonoids (apigenin and luteolin), and a large number of secoiridoid derivatives, this technique enables the identification of several new phenolic components, which had not been reported previously as constituents in the polar part of olive oil.